Single stage continuous paper making process and apparatus



March 22, 1960 N. SHOUMATOFF SINGLE STAGE CONTINUOUS PAPER MAKINGPROCESS AND APPARATUS Filed June 16, 1958 M 2 D A R 4 m s an s m U E .dV M m 4. ms m m 2 P m v 0 mm W 1 Pa M a H 2 NICHOLAS SHouMm'oFF UnitedStates Patent SINGLE STAGE CONTINUOUS PAPER MAKING PROCESS AND APPARATUSApplication June 16, 1958, Serial No. 742,218 12 Claims. (Cl. 162-313)This invention relates to the manufacture of paper and has for itsprincipal object the development of a method and apparatus for achievingthe complete manufacture of pulp into a formed and dried paper web at asingle .pass of less than a complete revolution upon the surface of acontinuously rotary drum.

To this end it is a feature that means is provided for evenly depositingslightly moist pulp, desirably containing substantially no more than 67%moisture, wet basis, at a pulp receiving station on a continuouslyrotary drum which has an uninterrupted pervious circumferential zone.The pulp so deposited is continuously forwarded on the surface of thedrum while confined out of contact with the atmosphere between thesurface of the drum and a traveling, impermeable, flexible, heatconductive band or belt. Steam is applied under pressure tothe outerside of the belt, and suction is applied to the inner surface of thepaper web from within the drum. The steam is first utilized primarilyfor its pressure effect to press the liquid out of the web and into thedrum, although the steam serves also during this pressing stage to heatthe liquid and thereby lower its viscosity. As the web contained liquidbecomes reduced below the concentration at which it can be mechanicallyexpressed, the action of the unit changes progressively from that of amechanical press to an evaporating drier. The steam pressure presses thebelt hard against the web, maintaining it in intimate and efficient heatconductive engagement therewith. At the same time the suction exertedfrom within the drum maintains the web under a substantial vacuum andthereby lowers the boiling point of the liquid while serving also tosuck away the vapors. The result is that a very rapid and effectivedrying action is secured.

, A combined pressing and drying unit of the kind above referred to butadapted to act only upon an already formed web, is disclosed and claimedin my pending application, Serial No. 652,302, filed April 11, 1957, forApparatus for Drying Web Material, and such unit per .se does notbroadly constitute a feature of the present invention.

It is, however, a very important feature of the invention that a unit ofthis kind is combined with means which deposits evenly on the drum a webforming pulp which is only slightly moist. The combination is importantfor the reason, among others, that the web forma tion does not, as isusual in cylinder machines, require the cylinder to run partiallysubmerged in a body of liquid. It is possible therefore to utilizealmost the entire circumferential extent of the forming drum forpressing and drying, and this without the retarding of pressing anddrying induced by the periodic chilling which .would occur if the drumwere required to operate in a partially submerged state.

Even though the drumis used for web forming, it is possible to steamjacket all or any desired part of the ;.drum and to utilize the heat andpressure of the steam with full effect and efliciency substantiallythroughout the jacketed arc.

The slightly moist pulp may be deposited on the drum in an arc of thedrum which is not subject to superatmospheric pressure either in a steamentrained condition or by a mechanical means. More advantageously,however, the pulp is deposited upon an arc of the drum which is undersuperatmospheric pressure, and for this purpose it is an importantfeature that steam injector means is provided, constructed and arrangedto conduct the pulp into the pressure area and to deposit it in a steamentrained condition. The combination of r a unit having its pressurearea extended to include the pulp receiving station, with steam injectormeans for delivering the pulp to such station in a steam entrainedcondition is regarded as an important feature of the invention.

It is a further feature that the endless impervious pressure band orbelt is housed substantially completely within the steam jacket whichextends around the drum, the result being that the band is heated ratherthan cooled in that portion of its travel in which it is out of bearingrelation with the drum.

Other objects and advantages will hereinafter appear.

In the drawing forming part of this specification,

Fig. 1 is a view in sectional elevation of a practical and advantageousform of paper making machine embodying features of the invention, thesection being taken on the line 1-1 of Fig. 2, looking in the directionof the arrows; and

Fig. 2 is a view in sectional elevation on a larger scale than Fig. l,the section being taken on the line 2-2 of Fig. 1, looking in thedirection of the arrows.

The machine 10 comprises a closed housing 12 in which a paper web isformed from pulp, pressed and dried. The housing 12 provides a pressurechamber to which steam is delivered by the conduit 14 and from whichcondensate is discharged through a conduit .16. Any desired steampressure may be employed so long as the resulting temperature is notsufficiently high to discolor or otherwise damage the Paper fibers.

The drum 18 is rotatively mounted in the housing 12. At one end the drumis fixedly secured on a shaft 20 which is rotatably mounted in a bearing22 of the housing 12, the shaft also having fast upon it a driving gear24 through which it is continuously driven at uniform speed by suitabledriving mechanism (not shown). At the opposite end the drum has fastwith it a hollow journal member 26 which is rotatably supported in. a

bearing 28 of the housing 12. The drum 18 has a wide uninterrupted,perforated, circumferential zone, and may advantageously be made toinclude a steam and water pervious felt cover (not shown). I

Within the drum 18 a trough 30 is provided which includes arms 32 bywhich it is supported in a pendent condition from the shaft 20 and thejournal 26. The trough 30 serves to collect water which is mechanicallypressed from the web into the drum, and any water which may be formed bycondensation of steam within the drum. A suction pipe 34 extends throughthe hollow journal 26 and has a fixed downturned end 35 which terminatesin close proximity to the trough. The pipe serves to withdraw water fromthe trough when water is present, and to withdraw steam when no water ispresent.

A housing member 36 of channel-like construction is supported inproximity to the periphery of the drum by a bracket 38. The housing 36is connected to a suitable source of suction through a conduit 40, andconreases 67%. moisture (wet basis) isfed from a reservoir 42 by a screwconveyor 44 into a manifold conduit 46. Steam discharged under pressureinto manifold 46 under the control of a manually settable valve 47 froma conduit 48, picks up and eritrains the pulp 49 and carries it throughangularly disposed branch conduits 50 and nozzles 52 onto the drum 18 ata web forming station. A recirculating loop 53 is provided formaintaining adequate velocity of the pulp and steam to prevent pluggingof the pipes. The pulp 49 is carried under a thin, impervious, metallic,pressure band or belt 54 which is more than wide enough to cover thepervious zone of the drum 18. As the pulp encounters the band pressureit is flattened and evened iii thickness. i

The impervious band 54 may be of any suitable thin, strong, flexible,non-rustable, heat conductive material, stainless steel being apreferred material. The band 54 istrained to run on a plurality of idlerrollers 56, all of which are borne internally by the end ,walls of thehousing 12. The band is driven by the paper web from the drum 18, andruns in unison with the paper web. As the web travels initially betweenthe band and the drum, it contains suflicient moisture to admit ofsqueezing out through pressing. The. steam exerts a pressure upon thepaper web through the band of a different order of magnitude from thatwhich could be secured by a mere tensioning of the band, causing thepaper web to be heavily compressed, and causing a substantial part ofthe web contained water to be pressed out of the web and sucked into thedrum. This action is made more effective because the heat furnished tothe web from thesteam lowers the viscosity of the water.

As the web continues its advance, there is a gradual and progressivechange of operating effect from that of a mechanical press" to thatof anevaporating drier. This is brought about by the diminishing watercontent of the web and the continued heating of the web. The drying byevaporationis aided, of course, by (1) the high temperature of the steamin the housing 12, (2) the high pressure of the band 54 against the web,which serves both to improve the conductance of heat into. the webthrough the boundary between the band and the web, and also to improvethe conductivity of the web itself through a compacting of the web, (3)the lowering of the. boiling temperature of the liquid inthe web byreason of the fact that the interior of the drum, and the web itself,are: maintained under a substantial vacuum, and (4) the, continual andprompt withdrawal of the vapors from the Web by the suction maintainedwithin the drum.

'As has been pointed out above, the. drier featuresper se are disclosedand claimed in my pending application Serial No. 652,302. The presentinvention, however, is characterized by the fact thatthese advantagesare provided over an extensive arc of the same drum upon which thewebforming material is deposited in the form. of a thick pulp.Notwithstanding thefact thatthe drum 18 serves the function of a webforming cylinder,- there is relatively little water to extract, andthereis, noneed for the drum to run partially submerged. r

The fact that steam, rather than water, serves as the entraining mediumfor the pulp has anurnber of advantages, (1) it enables thepulp to bedeliveredin fluid suspension without the employment. of a. great excessof liquid, thereby avoiding the need for filteringout and disposing of agreat quantity of water, 2-) it tends to eyeri out the distribution ofthe fibersacross thedrurn and to dispose them completelywithoutorientation so that a grainless paper having great thoughness'in thecrossmachine direction will result, (3) the vehicle steam asit"s'eparates' from the. pulp within the housing 12 simply mingles withthe steam introduced through the conduit 14, contributingitsmassand itslatent heatto the pressiire steam, and (4) it cooperates with thehousing 12 and band 54 to keep the pulp web free ffrom contaminahat'thsstea .assent d. r wns-fi been formed drum periphery and collected in thedrum 18 will be pure enough for use as steam in pipes or heat exchangeelements, with or without pressure and temperature boosting.

The formed and dried paper web 58 is conveyed away from the drum 18through a peripheral exit opening of the housing 12 between the band 54and a sealing roller 60. Beyond the ends of the roller 60 and the finalidler roller 56, the drum is provided with sealing webs 62, 64, 66 whichbear against the ends of said roller. These webs may be provided withstrips or facings of any suitable material, desirably including afacing, at least, of a highly anti-friction material such as Teflon.Sealing strips 68 and 70 are also provided for closing the spacesbetween the periphery of the final idler roller 56 and the housingperiphery, and between the sealing roller 60 and the housing periphery.

In order to prevent possible contamination of the finished web bysplashed or floating pulp fibers, the housing 36 and the bracket 38 aremade jointly to form a solid barrier between the nozzles 56 and thedischarge end of the band 54.

It is a feature of considerable importance that the band 54 iscompletely contained within the steam pressure housing 12, and that ithas only a negligibly short portion exposed to the atmosphere adjacentthe point of web discharge. The band is thus caused to be heated ratherthan cooled when traveling out of bearing relation with the drum 18.

The illustrative machine may be supported in any suit able manner. Asshown, two I-beams 72, carried by a frame structure (not shown), havethe housing suspended from them.

While certain preferred embodiments of the invention have beenillustrated and described in detail, it is to be understood that changesmay be made therein and the invention embodied in other structures. Itis not, therefore, the intention to limit the patent to the specificconstruction illustrated, but to cover the invention broadly in whateverform is principles may be utilized. 2 v

I claim:

I. A single stage paper making machine comprising, in combination, arotary suction drum having a circumferential water pervious zone in itsperipheral wall, an impervious, endless, flexible, heat conductive belthaving an active stretch running around the major portion of the inbearing relation thereto, means for hurling moist, web-forming fibersevenly onto the drum in an area which is clear of the belt, meansforming with the drum an enclosure in which the active stretch of thebelt is substantially completely contained, and means for introducinghot fluid under pressure intothe enclosure to serve as an evaporatingheat and pressure supplying. medium for pressing the belt againstthe weband transmitting heat through the belt to the web, and means,cooperrating with the belt for feeding the dry web, which has and driedon the drum, away from the pressure zone defined by the enclosure.

2. A single stage paper making machine comprising, in combination, arotary suction drum having a circumferential water pervious zone in itsperipheral wall; an im pervious, endless, flexible, heat conductive belthaving an active stretch running around the major portion of the drumperiphery in bearing relation thereto, means for hurling steamentrained, moist web-forming fibers evenly onto the drum in an areawhich is clear of the belt, means forming with thedrum an enclosure inwhich the belt is substantially completely contained, and means forintroducing steam into the enclosure to serve as an-evaporating heat andpressuresupplying medium for pressing the belt against the web andtransmitting heat through the belt. to the web, and means cooperatingwith the belt for feeding the dry web, which has been formed and driedon the away from the pressure zone defined by the enclosure,

1; 3, Asinglestagetpaper makingmachine comprising in -combination, arotary suction drum having a circumferential water pervious zone in itsperipheral wall, an impervious, endless, flexible, heat conductive belthaving an active stretch running-around the major portion of the drumperiphery in bearing relation thereto, means for 4 hurling moist, webforming fibers evenly onto the drum, in an area which is clear of thebelt, means forming with the drum an enclosure in which the belt issubstantially completely-contained, means for introducing steam into theenclosure to serve as an evaporating heat and pressure supplying medium,and means cooperating with the belt for feeding the dry web which isformed and dried on the drum away from the pressure zone defined by theenclosure.

4. A single stage paper making machine comprising, in combination, meansforming a sealed enclosure, including a casing, a foraminous, rotarysuction drum in the enclosure, an'imperviou's, endless, flexible, heatconductive belt disposed within the casing and having an active stretchrimning around the major portion of the drum periphery in bearingrelation thereto, means for evenly hurling a thick, pulpy, web-forming,fibrous mass onto an area of the traveling drum which is clear of thebelt but within the enclosure, means for introducing hot fluid underpressure into the casing to serve as an evaporating heat and pressuresupplying medium, and means for feeding the dry web which has beenformed and dried in the enclosure away from the pressure zone around thesuction drum which is defined within the enclosure.

5. A single stage paper making machine comprising, in combination, meansforming a sealed enclosure, including a casing, a forarninous, rotarysuction drum in the enclosure, an impervious, endless, flexible, heatconductive belt disposed within the casing and having an active stretchrunning around the major portion of the drum periphery in bearingrelation thereto, means for evenly hurling a thick, pulpy, web-forming,fibrous mass onto an area of the traveling drum which is clear of thebelt but within the enclosure, means for introducing steam underpressure into the casing to serve as an evaporating heat and pressuresupplying medium, and means for feeding the dry web which has beenformed and dried in the enclosure away from the pressure zone around thesuction drum which is defined within the enclosure.

6. A single stagepaper making machine comprising, in combination, meansforming a sealed enclosure, including a casing, a foraminous, rotarysuction drum in the enclosure, an impervious, endless, flexible, heatconductive belt disposed within the casing and having an active stretchrunning around the major portion of the drum periphery in bearingrelation thereto, means for evenly spraying a thick, pulpy, web-forming,fibrous mass onto an area of the traveling drum which is clear of thebelt but within the enclosure, means for introducing steam underpressure into the casing to serve as an evaporating heat and pressuresupplying medium, and feeding rollers constituting part of the enclosureforming means and complementary to the casing, for feeding the dry webwhich has been formed and dried in the enclosure away from the pressurezone around the suction drum which is defined within the enclosure.

7. A single stage paper making machine comprising, in combination, meansforming a sealed enclosure, including a casing, a foraminous, rotarysuction drum in the enclosure, an impervious, endless, flexible, heatconductive belt disposed within the casing and having an active stretchrunning around the major portion of the drum periphery in unisontherewith and in bearing relation thereto, steam injector means forevenly hurling moist, steam entrained, web-forming fibers onto an areaof the traveling drum which is clear of the belt but within theenclosure, means for introducing steam under pressure into the casing toserve as an evaporating heat and pressure supplying medium, and feedingrollers constituting part of the enclosure forming means andcomplementary to the casing,

the enclosure, an impervious, endless,

(6 ing not substantially more suction drum which is defined for feedingthe dry web which has been formed and dried in the enclosure away fromthe pressure zone around the by the enclosure.

8. A single stage paper making machine comprising, in combination, meansforming a sealed enclosure, including a casing, a foraminous, rotarysuction drum in flexible, heat conductive belt disposed within thecasing and having an active stretch running around the major portion ofthe drum periphery in bearing relation thereto, means for evenly hurlinga thick, pulpy, web-forming, fibrous mass onto an area of the travelingdrum which is clear of the belt but within the enclosure, means forintroducing steam under pressure into the casing to serve as anevaporating heat and pressur e supplying medium, and feeding rollersconstituting part of the enclosure forming means and complementary tothe casing, for feeding the dry web which has been formed and dried inthe enclosure away from the pressure zone around the suction drum whichis defined within the enclosure, the belt and suction drum cooperatingfirst to form a mechanical water press for expressing water from theweb, and thereafter, as the water content is progressively depleted, toform an evaporating heater and vapor extractor, the construction andarrangement being such that the material which entered the enclosure asdiscrete moist fibers, leaves the enclosure in the form of a dry paperweb.

9. A single stage paper making machine comprising, in combination, meansforming a sealed enclosure, including a casing, a foraminous, rotarysuction drum in the enclosure, an impervious, endless, flexible, heatconductive belt disposed within the casing and having an active stretchrunning around the major portion of the drum periphery in bearing andsealing relation thereto, means for evenly hurling a thick, pulpy,web-forming, fibrous mass onto an exposed area of the traveling drum,means for introducing steam under pressure into the casing to serve asan evaporating heat and pressure supplying medium, and feeding rollersconstituting part of the enclosure forming means and complementary tothe casing, for feeding the dry web which has been formed and dried inthe enclosure away from the pressure zone which is defined around thesuction drum and within the enclosure, the construction and arrangementbeing such that the band and drum are exposed substantially continuouslyto a surrounding environment of steam under super-atmospheric pressure.

10. A single stage paper making machine comprising, in combination,means forming a sealed enclosure which includes a casing, a foraminous,rotary suction drum in the enclosure, an impervious, endless, flexible,heat conductive belt disposed within the casing and having an activestretch running around the major portion of the drum periphery inbearing relation thereto, means for evenly hurling a thick, pulpy,web-forming, fibrous mass onto an exposed area of the traveling drum,means for introducing hot fluid under pressure into to the casing toserve as a heat and pressure supplying medium, means for withdrawingsteam from the interior of the drum comprising a suction conduit whichincludes a suction housing disposed in the enclosure between the drumand the casing and extending across the pervious circumferential zone ofthe drum, said housing having an open intake side which directly facesthe drum, the construction and arrangement being such that steam whichis drawn from the web into the drum from the permeable zone of the drumis drawn outward from the drum through the permeable zone and thencethrough said housing, and means for feeding thedry web which has beenformed, pressed and dried on the drum away from the drum.

11. The method of forming, pressing and drying a paper web at a singlecontinuous passage of less than one complete revolution upon the surfaceof a drum, which comprises evenly hurling fibrous material containthan67% moisture, wet basis,

ata pulp receiving stationionto a' drum which has a circumferential,pervious zone, continuouslylforwarding the pulp on the surface of thedrum' while. confiningxit between the surface of the drrum andauf'overlying;v impermeable, flexible, heat-conductive belt,ap'plyingsuctin 12. The method of forming, pressing anii' drying'a paperweb at a single continuousipassage cfrle'sshtham one Completerevolutionupon the surface of a" drum, which comprises evenly hurlingsteam borne fibrous, web forming material containing not substantiallymore" than 67%moisture, wet basis,.at a pulp; receiving station, fonto adrum which has a'circumferential; petvious'zone; conthrough the belt, Ithe web at sub-atmospheric pressure by heat transmitted 10 away from thedrum and belt.

- t-iimously forwarding thepulp on the surfaceof-thc: drum -whilcconfining it 'betwe'en the; surface of the. drutnland an overlying,impermeable, flexible, heat-conductivebelt, applying suction to the. webfrom within the drum and concurrently applying steam under pressure't'othe outer side of the belt, first to mechanically squeeze moisture fromthe web into the drum by steam pressureexertd and then to evaporatemoisture; from from the steam through the belt, and web, which has beenformed conducting the: dry and dried on the drum,

References Cited in the file of this patent UNITED STATES PATENTS" 5 1,161', 74 7 Stamets NW2;

2,473,270 Adams June 14, 19 9 FOREIGN PATENTS.

736,592 Germany 22 1943

